Sure, there were some new rules and benefits over the last few years, but that was just a warmup. Starting today, all of the big pieces of the Affordable Care Act — the biggest domestic achievement of Barack Obama’s presidency and one of the most far-reaching changes in American social policy in decades — go into effect. And Americans will start to see, for better or worse, how the law really works.

Private health coverage starts for more than 2 million Americans who managed to get through that federal enrollment website or the state-run versions. People with pre-existing conditions can’t be turned down anymore. Subsidies will start to help low- and middle-income people pay for their insurance.

The expansion of Medicaid begins, and as many as 3.9 million more low-income Americans are in line to get that coverage. And yes, the individual mandate kicks in to require just about all Americans have some kind of health insurance or pay a fine.

But it’s only going to be accepted as a “big deal,” as Obama put it before the holidays, if the rest of America decides it was worth the trouble. The Affordable Care Act has already survived a series of near-death experiences, from the rocky passage to the Supreme Court challenge in 2012 to that enormous self-inflicted wound known as the HealthCare.gov rollout.

Now, it has a whole new series of hurdles it has to clear — starting with a late New Year’s Eve order by Supreme Court Justice Sonia Sotomayor that blocked the law’s contraceptive coverage requirement. The order affected only one Catholic-affiliated group in Denver, but it’s part of a huge cultural flashpoint that’s heading to the Supreme Court this year.

Obamacare supporters and the president and his team can bask for just a moment in the glow of their long-sought goal finally becoming law — but only for a moment. The ACA’s Perils of Pauline debut is going to continue. Here are the obstacles ahead this year:

The big challenge: Changing the narrative

After three solid months of “botched rollout” stories, Democrats will have to hope that the reality of new health coverage for millions of Americans will be enough to outweigh the disruption the law is causing to millions of others.

Even now, top Democrats are convinced that, at some time during the year, there will be a natural tipping point. Enough people will either have coverage through the law or know someone who’s benefiting from it, they say, that Democrats will be able to put Republicans on the defensive about wanting to take their benefits away.

Joel Benenson, Obama’s pollster, is already playing down the threat of any lasting damage from the rollout. He insists that most Americans “want leaders in Washington taking actions that will strengthen their economic security and keep growing jobs and our economy” — a signal that the administration still believes the Affordable Care Act can be part of a broader economic security message.

“The only people obsessed with the ACA rollout today are Washington insiders,” Benenson said in an email, noting that “we have had a presidential campaign and a year in Congress where those who advocated for repeal of Obamacare lost.”

Other Democrats are quicker to acknowledge that the past few months have hurt the Obamacare cause. But they still believe the politics will turn around when more people have health coverage who could never get it before, especially people with serious health problems.

“The hard reality is that, particularly in October, the vast majority of people who tried to sign up had a terrible experience,” said Democratic Rep. Rob Andrews of New Jersey. And “if I had one thing to do over again,” he said, it would have been to give the people with substandard individual health plans a warning that they’d have to upgrade — saying, in effect, that “you can still buy a car without seat belts and airbags, but that day is going to change.”

But over the course of 2014, Andrews said, it will be clear to most Americans that the law doesn’t touch them — so Republicans who keep attacking it as a fundamental threat to their health care will have “a Chicken Little problem.”

Republican pollsters aren’t so sure about that. The storyline of government incompetence and disruption is so firmly in place by now, they say, that even if Democrats could line up a series of “don’t take my benefits away” events with cancer survivors and other sympathetic people, it wouldn’t make a big difference.

“There’s a very big filter that’s been locked into place, so the amount of information that would be required to break through that filter would be substantial,” said Republican pollster Bill McInturff.

Starting the coverage

The first specific hurdle the health care law has to clear, starting today, is the beginning of private health and Medicaid coverage for millions of Americans. It has to start smoothly, without a lot of horror stories of people showing up at doctors’ offices without coverage or being confused by what’s actually covered.

And, of course, Obama administration officials are hoping they’ve done enough to get through the next few weeks without a “coverage gap” — people who are suddenly uninsured because they couldn’t replace their canceled policies in time.

They’re hopeful that, between people’s ability to renew directly with their insurers, a better and faster federal website to enroll others, extensions of old health plans in some states through Obama’s administrative fix, and slimmer “catastrophic” health plans for people who can’t get those extensions, they’ve given people plenty of options to replace their coverage. But they’ll be watching closely, just in case.

Even if they can get through the first few weeks without more fires breaking out, they’ll have to turn to the next phase of the debate, which will turn on whether more people think they got good deals or pricey health plans without enough doctors.

“It will be a more granular-level debate that will focus on the price and the quality of the plans,” said former Obama spokesman Ben LaBolt. “Republicans will focus on people whose costs went up, Democrats will focus on people who didn’t have coverage before who had it now.”

White House officials say they’re planning to keep up the recent blitz of events promoting the benefits of the law, working with advocacy groups to highlight people who have gained coverage.

LaBolt also predicted that, once insurers start spending money to promote the law — which is now starting to happen — some of the advantage opponents have enjoyed through their well-funded advertising campaigns will start to disappear. “That landscape is about to change,” he said.

But Republican pollster David Winston, who advises the House GOP leadership, says the administration still faces a big danger from people who believe the law is hurting the quality of their own care — and that Obama won’t be able to regain the credibility he lost with the broken “you can keep your health plan” promise.

Enrolling enough people

By the end of March, there will be another moment of suspense: Can the Obamacare health insurance exchanges enroll enough people — or at least the right mix of people?

The open enrollment period for 2014 ends on March 31, so there could be another wave of last-minute signups. But the administration has been backing away from its early suggestions that 7 million people would be the goal for the exchanges — a number that came from the Congressional Budget Office estimate of how many people would enroll in the first year.

Instead, they’re now saying that even a smaller number would be fine, as long as there are enough young and healthy people to keep the health plans financially stable.

And even though it’s not clear yet whether that’s happening, they’re convinced that it will happen by the end of March, because they expect a big wave of people to sign up at the last minute — mostly people who didn’t have any reason to enroll earlier.

“We are focused on the long game for March 31,” said one White House official, because the experience of Massachusetts — which paved the way for Obamacare with its own health reform law in 2006 — “shows that people come in at the end.”

Back to the courts

This spring, there will be a bit of a Supreme Court flashback as the law goes back to the high court, this time on whether its contraceptive coverage requirement should be struck down or limited.

Sometime this spring, the justices will hear one hour of arguments on two challenges to the mandate, which requires most large employers to cover FDA-approved contraceptives at no cost to their workers. Then, the court will rule on whether private companies should should be forced to provide the coverage if the owners have religious objections to it. That’s a candidate, once again, for one of the final rulings of the Supreme Court session — meaning it would come out at the end of June.

But the mandate is already before the court in a more limited way. Sotomayor’s ruling Tuesday night blocked the requirement for a Denver home for the elderly that’s run by Catholic nuns. The government has to respond to the order by 10 a.m. Friday. It’s technically a narrow ruling, but any further action from the court could have a much broader reach.

The contraception requirement isn’t as central to the law as the individual mandate, the focus of the law’s previous trip to the high court, in 2012. But it has set off a huge culture clash with social conservatives, and at this point both the administration and the opponents would be happy to just get the issue resolved.

The political fight, of course, won’t go away that easily. If the mandate is struck down, it would be another huge political blow to the law, even though it wouldn’t prevent the rest of the law from functioning. If the justices uphold it, the administration will be able to say it has been vindicated yet again — but Republicans and religious conservatives won’t stop attacking it as a violation of employers’ religious beliefs.

Democrats, however, don’t think it’s going to work out well for Republicans to keep arguing against a benefit that has been so popular with women voters. “Anyone who’s on the side of a woman’s boss being able to decide what her birth control coverage is, I wouldn’t want to be on that side of the argument,” said Andrews.

Dealing with Congress

On Capitol Hill, the threat to the law isn’t so much another series of repeal or defunding votes. It’s the ongoing series of hearings Republicans will hold to keep any implementation problems front and center — and the constant danger of red state Democrats calling for their own rewrites to the law.

It’s not impossible that House Republicans will hold more votes to delay parts of the law and that they could draw large numbers of Democratic votes. That’s an especially strong possibility if Republicans try again to delay the individual mandate, since the administration has already had to delay so many other, smaller deadlines in the law as the implementation falls behind schedule.

But the main focus in the House will be the hearings, since Republicans are convinced their best shot at keeping repeal hopes alive is to highlight every problem that can be linked to the law.

“While there may be additional targeted legislative strikes, the heavy emphasis will be on oversight,” said Brendan Buck, a spokesman for House Speaker John Boehner. “The law can’t truly be ‘fixed,’ so we’ll be making the case for repeal by highlighting the endless negative consequences of the law.”

And in the Senate, Democrats in close reelection races — like Jeanne Shaheen of New Hampshire and Mary Landrieu of Louisiana — will keep up their public push for changes, all part of an effort to show they’re leaning on the White House to fix implementation problems.

The Obama administration has already shown that it’s going to take outreach to these Democrats more seriously — especially with the return of Phil Schiliro, who headed the push for the health care law. Schiliro has “deep, personal relationships with a significant number of members” and “knows the health law inside and out,” so he should be able to convince them the administration is working with them to smooth the law’s implementation, according to a senior Democratic aide.

That’s probably not going to be enough to keep the Shaheens and the Landrieus from pushing for legislative fixes, but they shouldn’t hold their breath for the Senate to vote on them. These Democrats may just get more space from the leadership to distance themselves in public from the implementation problems.

“They’re going to have to do what they have to do, but the caucus is in a different place right now” after the repairs to the website, said one Democratic strategist with ties to the Senate leadership.

The elections

This will be the first time Democrats have faced the voters when the main parts of the Affordable Care Act are in force — so it will be the most important referendum yet.

Will Democrats actually run on it? If it has enrolled enough people and seems to be working in a recently competent way, they might. But it’s no sure thing, especially if other fires break out during the fall, during the height of election season. That’s especially possible if some small businesses start facing premium hikes, which could hit in October, as they switch to health plans that comply with the law’s new pricing rules.

Democrats may be able to get off the defensive, but “I don’t think there’s going to be a whole lot of people running on it,” said Democratic pollster John Anzalone. The implementation is sure to improve and they’ll be freed up to talk about other issues, he said, but “I don’t think there’s going to be a ‘told you so’ moment for Democrats.”

But freshman Rep. Joe Garcia of Florida, one of the most endangered House incumbents in the country, insists he won’t be afraid to talk about it at all.

“As this rolls out, I run into more and more people who shake my hand, their eyes watering at what they’ve been able to accomplish” by signing up for health insurance, Garcia said late last month after he’d returned to his district for the holidays. “This may not be perfect, but nothing ever is.”

Garcia — who represents southern Florida, including the Keys — isn’t shy about bashing the sloppy website rollout: “First impressions are lasting ones, and the administration clearly ruined the first impression.” And he’s one of the House Democrats who votes for delays and legislative changes. He voted for the House Republican Keep Your Health Plan Act, for example, and has already supported a one-year delay in the individual mandate.

But he also insists that the goal of expanded health coverage is worth the effort, since one third of his constituents are uninsured.

“I’m in. I’m all in,” Garcia said. “If I get a few minutes to explain it to [a voter], I’ll tell you how you’ll be better off. If not, I didn’t expect to be buried in the Capitol anyway.”